** Shares of Woodside Energy WDS.AX marginally up 0.5% at A$26.74

** Jarden says decommissioning costs for Bass Strait is a key issue for investors and expects market to wonder if the change in operator for Woodside will result in higher provisions in the future

** Australia's top oil and gas producer on Tuesday said it will take over as operator of the Bass Strait oil and gas assets from ExxonMobil XOM.N, unlocking about $60 million in synergies

** Woodside said agreement does not affect decommissioning plans, added it has identified future development potential including four possible wells

** Brokerage estimates $2 billion as gross cost for Bass Strait decommissioning

** We think any investor enthusiasm for potential Bass Strait cost synergies and gas development will be tempered by uncertainty around Woodside's future Bass Strait decommissioning exposure - Jarden

** Brokerage retains "overweight" call, target price A$25.75

** Stock up 8.7% YTD, including the day's moves

(Reporting by Nikita Maria Jino in Bengaluru)

((Nikita.Jino@thomsonreuters.com;))